In multi-projector systems, a casually-arranged set of projectors can produce a large combined display having undesirable artifacts including projection overlaps due to geometric distortions caused by misalignment of the projectors, keystoning, and the like. These artifacts can be mitigated by calibrating the system using a camera.
In calibration, one or more calibration patterns are projected upon a display surface, and high-resolution digital images of the calibration patterns are captured by a digital camera. The captured images are processed to determine a correspondence between pixels of the camera and pixels of the projectors. This correspondence is used to transform image pixels to projector pixels for correcting the above-mentioned projection artifacts. However, the high-resolution calibration images captured by the camera can include large amounts of data.
Projector masks are commonly used during calibration to isolate calibration data for each projector. During calibration of each projector, a corresponding projector mask is used to extract the relevant data from the captured calibration images, thereby reducing the amount of data to be processed. However, in order to use this technique, the projector masks must be accurate.